Three-dimensional fusion imaging to assess apposition of low-profile visualized intraluminal support stent for intracranial aneurysm coiling

Objective

To investigate on three-dimensional (3D) fusion images the apposition of low-profile visualized intraluminal support (LVIS) stents in intracranial aneurysms after treatment and assess inter-rater reliability.

Materials and methods

Records of all patients with unruptured intracranial aneurysms who were treated with the LVIS stent were retrospectively accessed and included in this study. Two neurosurgeons evaluated the presence of malapposition between the vessel walls and the stent trunk (crescent sign) and the vessel wall and the stent edges (edge malappostion) on 3D fusion images. These images were high-resolution cone-beam computed tomography images of the LVIS stent fused with 3D-digital subtraction angiography images of the vessels. Associations between malapposition and aneurysm location were assessed by Fisher's exact test, and inter-rater agreement was estimated using Cohen's kappa statistic.

Results

Forty consecutive patients were included. In all patients, 3D fusion imaging successfully visualized the tantalum helical strands and the closed-cell structure of the nitinol material of the low-profile visualized intraluminal support. A crescent sign was observed in 27.5 % and edge malapposition in 47.5 % of the patients. Malapposition was not significantly associated with location (p = 0.23 crescent sign, p = 0.07 edge malapposition). Almost perfect (κ = 0.88) and substantial (κ = 0.76) agreements between the two raters were found for the detection of crescent signs and edge appositions, respectively.

Conclusions

3D fusion imaging provided clear visualization of the LVIS stent and parent arteries, and could detect malapposition with excellent inter-rater reliability. This technique may provide valuable guidance for surgeons in determining postoperative management.

Isocentric fixed angle irradiation-based DRR: a novel approach to enhance x-ray and CT image registration

OBJECTIVE

Digitally Reconstructed Radiography (DRR) plays an important role in the registration of intraoperative X-ray and preoperative CT images. However, existing DRR algorithms often neglect the critical Isocentric Fixed Angle Irradiation (IFAI) principle in C-arm imaging, resulting in inaccurate simulation of X-ray images. This limitation degrades registration algorithms relying on DRR image libraries or employing DRR images (DRRs) to train neural network models. To address this issue, we propose a novel IFAI-based DRR method that accurately captures the true projection transformation during X-ray imaging of the human body. Approach. By strictly adhering to the IFAI principle and utilizing known parameters from intraoperative X-ray images paired with CT scans, our method successfully simulates the real projection transformation and generates DRRs that closely resemble actual X-ray images. Main result. Experimental results validate the effectiveness of our IFAI-based DRR method by successfully registering intraoperative X-ray images with preoperative CT images from multiple patients who underwent thoracic endovascular aortic procedures. Significance. The proposed IFAI-based DRR method enhances the quality of DRR images, significantly accelerates the construction of DRR image libraries, and thereby improves the performance of X-ray and CT image registration. Additionally, the method has the generality of registering CT and X-ray images generated by large C-arm devices. .

Radiation exposure in navigated techniques for AIS: is there a difference between pre-operative CT and intraoperative CT?

PURPOSE

Utilization of navigation improves pedicle screw accuracy in adolescent idiopathic scoliosis (AIS). Our center switched from intraoperative CT (ICT) to an optical navigation system that utilizes pre-operative CT (PCT). We aim to evaluate the radiation dose and operative time for low-dose ICT compared to standard and low-dose PCT used for optical navigation in AIS patients undergoing posterior spinal fusion.

METHODS

A single-center matched-control cohort study of 38 patients was conducted. Nineteen patients underwent ICT navigation (O-arm) and were matched by sex, age, and weight to 19 patients who underwent PCT for use with an optical-guided navigation (7D, Seaspine). A total of 418 levels were instrumented and reviewed. PCT was either a standard dose (N = 7) or a low dose (N = 12). The mean volume CT dose index, dose-length product, overall effective dose (ED), ED per level instrumented, and operative time per level were compared.

RESULTS

ED per level instrumented was 0.061 ± 0.029 mSv in low-dose PCT and 0.14 ± 0.05 mSv in low-dose ICT (p < 0.0001). ED per level instrumented was significantly higher in standard PCT (1.46 ± 0.39 vs. 0.14 ± 0.03 mSv; p < 0.0001). Mean operative time per level was 31 ± 7 min for ICT and 33 ± 3 min for PCT (p = 0.628).

CONCLUSION

Low-dose PCT resulted in 0.70 mSv exposure per case and 31 min per level, standard-dose was 16.95 mSv, while ICT resulted in 1.34-1.62 mSv and a similar operative time. Use of a standard-dose PCT involves radiation exposure about 9 times higher than ICT and 23 times higher than low-dose PCT per level instrumented.

LEVEL OF EVIDENCE

Level III.

Role of Laser Pointer in Budgeting Fluoroscopy-Time and Radiation Exposure

BACKGROUND

Literature on radiation exposure with use of the mini C-arm and value of having built-in laser guidance is limited. The purpose of this study was to determine whether laser guidance use on a mini C-arm fluoroscopy unit can reduce radiation exposure.

METHODS

Surgeons (N = 25) performed the same simulated surgical task, which involved obtaining "perfect circle" views of 2 cannulated screws placed into a cadaveric wrist, done with and without C-arm laser guidance. The testing order was randomized. Main outcomes were time to complete the task, number of shots required to complete the task, number of blank shots taken, radiation exposure, total dose area product (DAP), and total exposure time.

RESULTS

Laser guidance significantly reduced the percentage of surgeons who took blank shots, from 88% of the group without the laser to 12% of the group with the laser, and decreased the total average blank shots in the group from 3.5 to 0.1. While we found laser guidance led to shorter time to complete the task, decreased shots taken, and decreased exposure time and DAP, these findings only approached significance.

CONCLUSION

While debate continues regarding whether mini or standard C-arm is safest, it is clear that decreasing the overall number of exposures limits potential adverse effects. Our study demonstrated that when using a mini C-arm, laser guidance decreases the number of exposures required to capture an image. These findings warrant a larger study to define the specific exposure savings and indicate potential benefit of mini C-arm use with laser guidance.

Implementation of a Specific Set of Intraoperative C-Arm Fluoroscopy Terminologies in Percutaneous Vertebroplasty

OBJECTIVE

Percutaneous vertebroplasty (PVP) is currently the primary minimally invasive surgical approach for treating vertebral compression fractures caused by senile osteoporosis. The current existing problem is the lack of research on the application of a specific set of intraoperative C-arm fluoroscopy terminologies in PVP. Therefore, the purpose of this study is to explore the use of a specific set of intraoperative C-arm fluoroscopic terminologies in PVP in order to increase fluoroscopy accuracy, decrease fluoroscopy frequencies and ray protection, and minimize operation times through rapid preoperative training of surgeons and radiographers.

METHODS

Spine surgeons and radiographers with at least 5 years of experience from nine different hospitals were randomly selected for a series of specialized intraoperative C-arm fluoroscopy terminology training between October 2018 and December 2021. Before and after the training, they were surveyed using a five-point Likert scale to statistically compare their knowledge of the terminology. Simultaneously, 190 PVP cases completed by these surgeons and radiographers before and after the training were chosen for comparison and analysis of fluoroscopy times, effective fluoroscopy rate, fluoroscopy time, repeated puncture rate, and other indicators before and after receiving specialized terminology training. Two-sample tests were mainly used to investigate differences in answers between surgeons and radiographers.

RESULTS

After the training, there was a notable improvement in the fluency of intraoperative communication between professional spine surgeons and radiographers. By comparing the indicators of pre-training with post-training, the effective anteroposterior fluoroscopy rate increased from 46.5% to 75.7%; the effective lateral fluoroscopy rate increased from 59.8% to 76.9%. Moreover, a notable decrease in communication barriers, fluoroscopy frequencies, fluoroscopy time, and the rate of repeated punctures, and a notable increase in the effective fluoroscopy rate was observed.

CONCLUSION

Smooth intraoperative communication between professional spine surgeons and radiographers can significantly lower the communication barrier, reduce the fluoroscopy frequencies and time, the rate of repeated puncture, and increase the effective fluoroscopy rate, all of which are important in improving the fluoroscopy in PVP.

Does radiation exposure during pediatric supracondylar humeral fracture surgery change according to the C-arm position? A comparison of two different techniques

INTRODUCTION

In the surgical treatment of supracondylar humeral fractures (SHF), the surgeon has to stand right next to the fluoroscopy device, so it is very important to know how to use it in the most appropriate way to reduce radiation exposure. The aim of this study was to investigate the effect of using C-arm in uniplanar (inverted) and biplanar (standard-horizontal) configurations on (1) the radiation exposure to the surgeon, and (2) surgical time and fluoroscopy exposure time.

MATERIAL AND METHODS

This prospective randomised study was conducted on 20 patients who underwent fluoroscopy during closed reduction and percutaneous pinning for a SHF. In the first configuration, the C-arm was inverted and the image intensifier was used as a surgical table. In the second configuration, the C-arm was used biplanar. The operations were performed by 5 surgeons, with each surgeon using each method only twice. During the operation, to find a value closed to direct radiation exposure measurement was made by attaching a dosimeter to the wrist and scatter radiation exposure was measured by attaching a dosimeter to the neck and waist of the surgeons. The operation time and fluoroscopy exposure time were determined.

RESULTS

The duration of operations performed with the biplanar C-arm position and the fluoroscopy exposure time in operations performed with the uniplanar method were found to be statistically significantly longer (p = 0.001). The measurements on the dosimeter worn on the neck of surgeons were found to be statistically significantly higher while using the uniplanar C-arm configuration (p = 0.001). There was no statistically significant difference between the dosimeter measurements on the wrists and waists of the surgeons and the C-arm configurations (p = 0.820; p = 0.185).

CONCLUSIONS

Although the use of biplanar C-arm has no effect on radiation exposure to the surgeon's wrist, the most important advantages are that the neck area is exposed to less radiation and it shortens the fluoroscopy time so the use of a biplanar C-arm can be recommended.

LEVEL OF EVIDENCE

Level II.

Endobronchial Radiofrequency Ablation for pulmonary nodules with Radial-Ebus and Navigation: Pros and Cons

Introduction: Pulmonary nodules are common in the everyday clinical practice. There is always a diagnostic issue with this imaging finding. Based on the size we can use a variety of imaging and diagnostic techniques. Moreover; in the case of primary lung cancer or metastasis we can use radiofrequency ablation endobronchially. Patients and Methods: We used the radial-endobronchial ultrasound with C-arm and Archemedes, Bronchus electromagnetic navigation in order to acquire biopsy sample and we also used rapid on-site evaluation as a rapid diagnosis for pulmonary nodules. After rapid diagnosis we used the radiofrequency ablation catheter in order to ablate central pulmonary nodules. Results: Both techniques provide efficient navigation, however, with the Bronchus system less time is needed. The new radiofrequency ablation catheter provides efficient results in central lesions with low watts ≤40. Conclusion: We provided in our research a protocol to diagnose and treat such lesions. Future larger studies will provide more data on this subject.

Cone-beam CT sampling incompleteness: analytical and empirical studies of emerging systems and source-detector orbits

Purpose

Motivated by emerging cone-beam computed tomography (CBCT) systems and scan orbits, we aim to quantitatively assess the completeness of data for 3D image reconstruction-in turn, related to "cone-beam artifacts." Fundamental principles of cone-beam sampling incompleteness are considered with respect to an analytical figure-of-merit [FOM, denoted tan(ψmin)] and related to an empirical FOM (denoted zmod) for measurement of cone-beam artifact magnitude in a test phantom.

Approach

A previously proposed analytical FOM [tan(ψmin), defined as the minimum angle between a point in the 3D image reconstruction and the x-ray source over the scan orbit] was analyzed for a variety of CBCT geometries. A physical test phantom was configured with parallel disk pairs (perpendicular to the z-axis) at various locations throughout the field of view, quantifying cone-beam artifact magnitude in terms of zmod (the relative signal modulation between the disks). Two CBCT systems were considered: an interventional C-arm (Cios Spin 3D; Siemens Healthineers, Forcheim Germany) and a musculoskeletal extremity scanner; Onsight3D, Carestream Health, Rochester, United States)]. Simulations and physical experiments were conducted for various source-detector orbits: (a) a conventional 360 deg circular orbit, (b) tilted and untilted semi-circular (196 deg) orbits, (c) multi-source (three x-ray sources distributed along the z axis) semi-circular orbits, and (d) a non-circular (sine-on-sphere, SoS) orbit. The incompleteness of sampling [tan(ψmin)] and magnitude of cone-beam artifacts (zmod) were evaluated for each system and orbit.

Results

The results show visually and quantitatively the effect of system geometry and scan orbit on cone-beam sampling effects, demonstrating the relationship between analytical tan(ψmin) and empirical zmod. Advanced source-detector orbits (e.g., three-source and SoS orbits) exhibited superior sampling completeness as quantified by both the analytical and the empirical FOMs. The test phantom and zmod metric were sensitive to variations in CBCT system geometry and scan orbit and provided a surrogate measure of underlying sampling completeness.

Conclusion

For a given system geometry and source-detector orbit, cone-beam sampling completeness can be quantified analytically (in terms arising from Tuy's condition) and/or empirically (using a test phantom for quantification of cone-beam artifacts). Such analysis provides theoretical and practical insight on sampling effects and the completeness of data for emerging CBCT systems and scan trajectories.

Fluoroscopy-Assisted Freehand Versus 3D-Navigated Imaging-Assisted Pedicle Screw Insertion: A Multicenter Study

INTRODUCTION

Pedicle screw placement is a widely accepted surgical procedure for spinal fixation. Despite increases in knowledge about and expertise in pedicle screw insertion techniques, overall reported screw misplacement rates are still high. Spinal neuronavigation and intraoperative computed tomography (CT) imaging improves the accuracy and safety of pedicle screw placement through the continuous monitoring of screw trajectory. The purpose of this study is to compare pedicle screw placement under an O-arm intraoperative imaging system assisted by the StealthStation navigation system with screw placement under conventional fluoroscopy (C-arm).

METHODS

For 222 patients, 1288 implanted pedicle screws in total were evaluated between 2018 and 2020. All patients underwent pedicle screw placement in the thoracic and lumbosacral regions through a posterior approach. Moreover, 107 patients (48.2%), 48 men and 59 women, underwent freehand screw placement under conventional fluoroscopy (C-arm group), whereas 115 patients (51.8%), 53 men and 62 women, underwent pedicle screw insertion under O-arm guidance with the help of the StealthStation neuronavigation system (Medtronic Navigation, Louisville, CO, USA) (O-arm group). Data were recorded and retrospectively analyzed. The accuracy of pedicle screw placement was postoperatively examined by using CT imaging and analyzed according to the Gertzbein-Robbins classification.

RESULTS

Of the 1288 pedicle screws, 665 (51.6%) were placed with C-arm image-guided assistance with a mean of 6.21 ± 2.1 screws per patient and 643 (48.4%) with O-arm image-guided assistance with a mean of 5.59 ± 1.6 screws. The average time for the screw placement procedure was 3:57 ± 1:07 h in the C-arm group and 4:21 ± 1:41 h in the O-arm group. A correct screw placement was detected in 92.78% of patients in the C-arm group and in 98.13% of patients in the O-arm group. Medial cortical breach was shown in 13 Grade B screws (1.95%), 19 Grade C (2.86%), 14 Grade D (2.11%), and two Grade E (0.3%) in the C-arm group, whereas this was shown in 11 Grade B screws (1.71%) and one Grade C (0.16%) in the O-arm group. Lateral breach occurred in eight screws in both groups. Anterior vertebral body breach was shown in eight screws in the C-arm group, whereas it was shown in four screws in the O-arm group. Reoperation for screw misplacement was mandatory in five patients in the C-arm group and two patients in the O-arm group.

CONCLUSION

Pedicle screw placement under an O-arm intraoperative imaging system assisted by spinal navigation showed greater accuracy compared with placement under conventional fluoroscopic control, thus avoiding the onset of major postoperative complications. Notably, a reduction in medial and anterior breaches has been demonstrated.

Single-Position Oblique Lumbar Interbody Fusion and Percutaneous Pedicle Screw Fixation under O-Arm Navigation: A Retrospective Comparative Study

The insertion of pedicle screws in the lateral position without a position change has been reported. We completed a retrospective comparison of the radiologic and clinical outcomes of 36 patients who underwent either single-position oblique lateral lumbar interbody fusion (SP-OLIF) using the O-arm (36 cases) or conventional OLIF (C-OLIF) using the C-arm (20 cases) for L2-5 single-level lumbar degenerative diseases. Radiological parameters were analyzed, including screw accuracy (Gertzbein-Robbins classification system; GRS), segmental instability, and fusion status. Screw misplacement was defined as a discrepancy of ≥2 mm. Clinical outcomes, including visual analog scale, Oswestry Disability Index (ODI), 36-Item Short Form Health Survey (SF-36), and postoperative complications, were assessed. The spinal fusion rate was not different between the SP-OLIF and C-OLIF groups one year after surgery (p = 0.536). The ODI score was lower (p = 0.015) in the SP-OLIF than the C-OLIF group. Physical (p = 0.000) and mental component summaries (p = 0.000) of the SF-36 were significantly higher in the SP-OLIF group. Overall complication rates, including revision, surgical site infection, ipsilateral weakness, and radicular pain/numbness, were not significantly different. SP-OLIF using the O-arm procedure is feasible, with acceptable accuracy, fusion rate, and complication rate. This may be an alternative to conventional two-stage operations.

Clinical Applications of Quantitative Perfusion Imaging with a C-Arm Flat-Panel Detector-A Systematic Review

C-arm systems with digital flat-panel detectors are used in interventional radiology and hybrid operating rooms for visualizing and performing interventions on three-dimensional structures. Advances in C-arm technology have enabled intraoperative quantitative perfusion imaging with these scanners. This systematic review provides an overview of flat-panel detector C-arm techniques for quantifying perfusion, their clinical applications, and their validation. A systematic search was performed for articles published between January 2000 and October 2022 in which a flat-panel detector C-arm technique for quantifying perfusion was compared with a reference technique. Nine articles were retrieved describing two techniques: two-dimensional perfusion angiography (n = 5) and dual-phase cone beam computed tomography perfusion (n = 4). A quality assessment revealed no concerns about the applicability of the studies. The risk of bias was relatively high for the index and reference tests. Both techniques demonstrated potential for clinical application; however, weak-to-moderate correlations were reported between them and the reference techniques. In conclusion, both techniques could add new possibilities to treatment planning and follow-up; however, the available literature is relatively scarce and heterogeneous. Larger-scale randomized prospective studies focusing on clinical outcomes and standardization are required for the full understanding and clinical implementation of these techniques.

Ultrasound guidance combined with C-arm fluoroscopy in selective semilunar ganglion radiofrequency thermocoagulation through foramen ovale for trigeminal neuralgia: A randomized controlled trial

OBJECTIVE

To explore the clinical value of ultrasound combined with C-arm guiding selective semilunar ganglion radiofrequency thermocoagulation via the foramen ovale for trigeminal neuralgia.

METHODS

This study enrolled 48 patients diagnosed with trigeminal neuralgia between January 2021 and December 2021 in the department of pain management at Xuanwu Hospital. Patients were randomly and equally divided into the C-arm group and ultrasound combined with the C-arm group, according to a random number table. After exclusions, 42 patients were analyzed. Among them, 21 cases underwent selective semilunar ganglion radiofrequency thermocoagulation via the foramen ovale guided by the C-arm, whereas 21 cases underwent the same guided by ultrasound combined with C-arm. The number and time of punctures, the accumulative doses for radiation exposure, and puncture-related complications were recorded during the operation. Numerical rating scale scores and radiofrequency thermocoagulation-related complications were evaluated preoperatively, at 1 day, 3 days, 7 days, 1 month, and 3 months after surgery.

RESULTS

The number and time of punctures and the accumulative doses for radiation exposure in the ultrasound-guided combined with the C-arm group were all lower than that in the C-arm-guided group (all P < 0.05). No significant difference was found in numerical rating scale scores and radiofrequency thermocoagulation -related complications between the two groups (P > 0.05). No puncture-related complications occurred in none of the groups.

CONCLUSION

Ultrasound guidance combined with C-arm in puncturing semilunar ganglion via foramen ovale could be safely used with more efficiency than C-arm guidance alone and less radiation exposure.

CLINICAL TRIALS REGISTRATION

This study was registered on the Chinese Clinical Trial Registry (NO. ChiCTR2100042124; http://www.chictr.org.cn/listbycreater.aspx), and the first patient enrollment began on January 18, 2021.

Two-dimensional C-arm robotic navigation system (i-Navi) in spine surgery: a pilot study

PURPOSE

Pedicle screws placement is very common procedure in spinal surgery. Robotic assisted surgery has been widely used in this operation. We assessed the accuracy of thoracolumbar spine trans-pedicle screws (TPS) implantation utilizing a noval robotic navigation system (i-Navi robotic navigation system) by planning with two-dimensional (2-D) C-arm.

METHODS

This study was approved by the Institutional Review Board of the Cathay General Hospital on June 21, 2018 (IRB number: CGH-P 106,092), and written informed consents were obtained from all the patients. There are 18 patients were enrolled in the study. All the patients received the posterior fusion with TPS insertion under the assistant of our robotic navigation system.

RESULTS

There are 18 patients were included into our study, there are 2 patients were quitted from the study due to the equipment setup was not complete. Other 16 patients completed the entire procedure successfully. There is total 88 pedicle screws were inserted through i-Navi robotic navigation system. There are 79 of 88 screws were graded A, and 9 screws were graded B; no screws were graded C or D. No vascular or nerve injuries were noted after the operations.

CONCLUSION

We present our i-Navi robotic navigation system, by planning with 2-D C-arm imaging and pre-operative CT scans. According to the results of study, we think it can provide a reliable and easy tool to perform the TPS in thoracic lumbar spine surgery.

C-arm contamination of the surgical field: Can contamination be reduced with an intervening drape?

INTRODUCTION

Contamination of the surgical field by the C-arm in orthopaedic procedures is a significant potential source for surgical site infections. The purpose of this study was to explore the utility of a split sheet to aid in prevention of secondary contamination from the C-arm on the C-arm side of the operative field.

METHODS

A C-arm and a surgical table were draped by standard techniques. The surgical table was split in thirds: the surgeon's side, the C-arm side of the operative field, and the middle for contamination analysis. Fluorescent powder was used to simulate a contaminant and placed on the C-arm, floor and lower portions of drapes. The C-arm was cycled between PA and Lateral positions. Powder transfer to the field was visualized with a camera under uniform UV light. Photographs were taken to measure fluorescent pixels prior to cycling the C-arm and at 5, 10 and 15 cycles. This protocol was repeated using a split sheet (U-drape) to isolate the C-arm below the operative field. Image J was utilized to calculate differences in the number of pixels brighter than the control image.

RESULTS

Using standard draping techniques, there was contamination of the surgical field with the C-arm side of the operative field having the highest level of fluorescent pixels. The number of fluorescent pixels was linearly correlated with the number of PA to Lateral cycles. At the end of 15 cycles, the average number of fluorescent pixels for the intervening draping technique was 2.9 pixels compared to the standard draping technique of 3939 pixels (p = 0.0078).

DISCUSSION

The addition of a U-drape between the C-arm and the table results in a statistically significant reduction in surgical field contamination as a result of secondary transfer from the C-arm.

LEVEL OF EVIDENCE

II.

Radiation-free Insertion of Interlocked Intramedullary Tibial Nail in Closed Extra-articular Displaced Tibial Shaft Fractures in an Emergency Setup

BACKGROUND

Interlocking nailing is considered a gold standard surgical treatment of mid-shaft closed diaphyseal tibial fractures. With increasing exposure of orthopaedic surgeons to radiation, we propose a solution to this health hazard through a study wherein we perform the surgery without any radiation or C-arm exposure.

MATERIAL AND METHODS

This prospective study was done at GMC Jammu from January 2017 to February 2020 and included 218 patients, with 18 patients having bilateral tibia fractures in the age group 15 to 58 years (mean of 37.6 years), including 63.7% males (n=139) and 36.3% females (n=79). The 236 extra-articular closed tibial mid-diaphyseal fractures were operated on and intramedullary tibial nailing was performed without a single C-arm exposure. Postoperative x-rays were done and reduction assessed by standard acceptable criteria.

RESULTS

Among 236 cases in which nailing was done, 227 (96%) patients were successfully distally locked, including 128 (56.3%) locked through the jig and 99 (43.6%) by "hit and trial method." All cases met acceptability criteria set for management of tibia by nailing.

CONCLUSIONS

1.This study strengthens the proof that closed extra-articular diaphyseal fractures of the tibia can be managed by nailing without using the C-arm with excellent results. 2.The C-arm is always available for cases where distal locking could not be achieved. 3. The technique has a great role in centres with limited facilities of intra-operative radiography in emergency operation theatres.

O-Arm Assisted Cervicothoracic Spine Pedicle Screw Placement Accuracy Is Higher Than C-Arm Fluoroscopy

OBJECTIVE

We compared the accuracy of C-arm fluoroscopy versus O-arm-assisted pedicle screw (PS) placement in the cervicothoracic spinal junction (CTSJ).

METHODS

Patients who underwent PS placement in the CTSJ (C7-T4) at our hospital were included in this study. Of 37 patients who underwent PS placement in the CTSJ, 20 underwent intraoperative C-arm fluoroscopy-assisted surgery (C Group) and 17 underwent intraoperative O-arm-assisted surgery (O Group). In total, 159 PSs were placed-73 in the C Group and 86 in the O Group. The accuracy of PS placement was compared between the C Group and O Group using the classification proposed by Gertzbein and Robbins to analyze pedicle violation.

RESULTS

PS accuracy was higher in the O Group than C Group; PS placement evaluated as grade A, representing no perforation, was 95.3% (82/86) for the O Group, whereas it was 78.1% (57/73) for the C Group. There was a clear statistically significant difference in accuracy of PS placement between the groups (P = 0.0013).

CONCLUSIONS

O-arm-assisted surgery improved the accuracy of PS placement in the CTSJ.

Three-dimensional catheter navigation of airways using continuous-sweep limited angle fluoroscopy on a C-arm

Purpose: To develop an imaging-based 3D catheter navigation system for transbronchial procedures including biopsy and tumor ablation using a single-plane C-arm x-ray system. The proposed system provides time-resolved catheter shape and position as well as motion compensated 3D airway roadmaps. Approach: A continuous-sweep limited angle (CLA) imaging mode where the C-arm continuously rotates back and forth within a limited angular range while acquiring x-ray images was used for device tracking. The catheter reconstruction was performed using a sliding window of the most recent x-ray images, which captures information on device shape and position versus time. The catheter was reconstructed using a model-based approach and was displayed together with the 3D airway roadmap extracted from a pre-navigational cone-beam CT (CBCT). The roadmap was updated in regular intervals using deformable registration to tomosynthesis reconstructions based on the CLA images. The approach was evaluated in a porcine study (three animals) and compared to a gold standard CBCT reconstruction of the device. Results: The average 3D root mean squared distance between CLA and CBCT reconstruction of the catheter centerline was 1 ± 0.5    mm for a stationary catheter and 2.9 ± 1.1    mm for a catheter moving at ∼ 1    cm / s . The average tip localization error was 1.3 ± 0.7    mm and 2.7 ± 1.8    mm , respectively. Conclusions: The results indicate catheter navigation based on the proposed single plane C-arm imaging technique is feasible with reconstruction errors similar to the diameter of a typical ablation catheter.

Heterogeneous Stitching of X-ray Images According to Homographic Evaluation

The C-arm X-ray system is a common intraoperative imaging modality used to observe the state of a fractured bone in orthopedic surgery. Using C-arm, the bone fragments are aligned during surgery, and their lengths and angles with respect to the entire bone are measured to verify the fracture reduction. Since the field-of-view of the C-arm is too narrow to visualize the entire bone, a panoramic X-ray image is utilized to enlarge it by stitching multiple images. To achieve X-ray image stitching with feature detection, the extraction of accurate and densely matched features within the overlap region between images is imperative. However, since the features are highly affected by the properties and sizes of the overlap regions in consecutive X-ray images, the accuracy and density of matched features cannot be guaranteed. To solve this problem, a heterogeneous stitching of X-ray images was proposed. This heterogeneous stitching was completed according to the overlap region based on homographic evaluation. To acquire sufficiently matched features within the limited overlap region, integrated feature detection was used to estimate a homography. The homography was then evaluated to confirm its accuracy. When the estimated homography was incorrect, local regions around the matched feature were derived from integrated feature detection and substituted to re-estimate the homography. Successful X-ray image stitching of the C-arm was achieved by estimating the optimal homography for each image. Based on phantom and ex-vivo experiments using the proposed method, we confirmed a panoramic X-ray image construction that was robust compared to the conventional methods.

A Novel Tracker-Less, Universal, Image-Based, Computer-Assisted Navigation in Orthopaedic Trauma- A pilot Study

BACKGROUND

Computer-assisted navigation system is well-known orthopaedic advancement which allow surgeon to obtain a real-time feedback during surgeries, thus helps to reduce intraoperative errors. Currently used navigation systems are tracker based, invasive and non-universal. Therefore this study was conducted to test novel tracker-less, image-based, non-invasive, universal, real-time navigation system to predict future position of the guide wire, K wire, screws and plates in orthopaedic trauma surgeries.

METHODS

Firstly, the software was tested and validated on bone model. Then utilized for non-randomised comparative study conducted on 81 adult patients with stable intertrochanteric fracture treated by dynamic hip screw and barrel plate fixation. In one group, C-arm was used and in other, software navigation was used in addition to C-arm. Parameters such as time to insertion, number of C-arm shoots and number of attempts for guide wire insertion were documented and compared.

RESULTS

Use of the navigation software for guide wire positioning in bone models and in the DHS barrel plate surgery proved to be significantly beneficial as compared to not using navigation.

CONCLUSION

Intraoperative use of this new navigation system eliminates trial and error improving accuracy and reducing the operative time and radiation exposure. Thus this novel trackerless, C-arm image-based navigation system have potential to replace existing tracker-based navigation systems because of its universal nature, noninvasive and more effective properties.

[Intraoperative computed tomography and modern navigation in surgical treatment of spine and spinal cord diseases]

Surgical treatment of spine and spinal cord diseases is one of important objectives in modern neurosurgery. Patient safety is a priority in spine and spinal cord surgery. Intraoperative imaging ensures efficacy and safe surgery with and without stabilization, preoperative marking, control of decompression and correct implant placement. Surgical C-arms and intraoperative cone-beam CT scanners are the most widespread in everyday practice. The latest achievement was intraoperative spiral computed tomography. C-arms and CT scanners with intraoperative navigation increase the efficiency and safety of surgical interventions.

Assessment of C-arm Confidence Among ASRT Graduate Bridge Program Members

PURPOSE

To identify the amount of C-arm preparation or instruction that recent graduates received in their radiography programs before starting clinical rotations and to determine whether completing more rotations increased their confidence in operating C-arm equipment.

METHODS

Members of the American Society of Radiologic Technologists' Graduate Bridge program who indicated a primary pathway in radiography received an invitation to complete the C-arm confidence survey and self-report their C-arm experiences during clinical education.

RESULTS

A third of the participants indicated they received preparation or instruction on C-arm equipment before beginning clinical rotations, with the majority of those indicating they had completed a C-arm laboratory. Almost half of the participants indicated that they were assigned to a minimum of 4 surgical rotations during their radiography program; nearly two-thirds indicated that they were not assigned additional clinical experience with C-arm equipment beyond those rotations.

DISCUSSION

Participants who completed 4 or more surgical rotations during their radiography clinical education reported significantly higher confidence levels regarding operating C-arm equipment compared with those participants who completed 3 surgical rotations (P = .005), 2 surgical rotations (P< .001), or 1 surgical rotation (P< .001). Those participants who completed more C-arm rotations reported significantly higher confidence in operating C-arm equipment than did those who completed only surgical rotations (P< .01). A Pearson correlation coefficient also revealed a significant positive relationship between participants' confidence levels after completing surgical and other C-arm rotations (P< .01). Participants' confidence levels increased after completing surgical rotations and other C-arm rotations such as in pain management and interventional radiography.

CONCLUSION

Program directors, clinical coordinators, and radiography educators should consider implementing specific instruction on C-arm use and assigning students to more clinical rotations to increase students' confidence in their C-arm skills.

The effect of artificial X-rays on C-arm positioning performance in a simulated orthopaedic surgical setting

PURPOSE

We designed an Artificial X-ray Imaging System (AXIS) that generates simulated fluoroscopic X-ray images on the fly and assessed its utility in improving C-arm positioning performance by C-arm users with little or no C-arm experience.

METHODS

The AXIS system was comprised of an optical tracking system to monitor C-arm movement, a manikin, a reference CT volume registered to the manikin, and a Digitally Reconstructed Radiograph algorithm to generate live simulated fluoroscopic images. A user study was conducted with 30 participants who had little or no C-arm experience. Each participant carried out four tasks using a real C-arm: an introduction session, an AXIS-guided set of pelvic imaging tasks, a non-AXIS guided set of pelvic imaging tasks, and a questionnaire. For each imaging task, the participant replicated a set of three target X-ray images by taking real radiographs of a manikin with a C-arm. The number of X-rays required, task time, and C-arm positioning accuracy were recorded.

RESULTS

We found a significant 53% decrease in the number of X-rays used and a moderate 10-26% improvement in lateral C-arm axis positioning accuracy without requiring more time to complete the tasks when the participants were guided by artificial X-rays. The questionnaires showed that the participants felt significantly more confident in their C-arm positioning ability when they were guided by AXIS. They rated the usefulness of AXIS as very good to excellent, and the realism and accuracy of AXIS as good to very good.

CONCLUSION

Novice users working with a C-arm machine supplemented with the ability to generate simulated X-ray images could successfully accomplish positioning tasks in a simulated surgical setting using markedly fewer X-ray images than when unassisted. In future work, we plan to determine whether such a system can produce similar results in the live operating room without lengthening surgical procedures.

Novel C-arm based planning spine surgery robot proved in a porcine model and quantitative accuracy assessment methodology

BACKGROUND

We assessed pedicle screw accuracy utilizing a novel navigation-based spine surgery robotic system by comparing planned pathways with placed pathways in a porcine model.

METHODS

We placed three mini screws per vertebra for accuracy evaluation and used a reference frame for registration in four pigs (46 screws in 23 vertebrae). We planned screw paths and performed screw insertion under robot guidance. Using C-arm and CT images, we evaluated accuracy by comparing the 3D distance of the placed screw head/tip from the planned screw head/tip and 3D angular offset.

RESULTS

Mean registration deviation between the preoperative 3D space (C-arm) and postoperative CT scans was 0.475 ± 0.119 mm. The average offset from preoperative plan to final placement was 4.8 ± 2.0 mm from the head (tail), 5.3 ± 2.3 mm from the tip and 3.9 ± 2.4 degrees of angulation.

CONCLUSIONS

Our spine surgery robot showed good accuracy in executing an intended planned trajectory and screw path. This faster and more accurate robotic system will be applied in future studies, first in cadavers and subsequently in the clinical field.

Dose simulations of an early 20th century kilovoltage pneumonia radiotherapy technique performed with a modern fluoroscope

To simulate an early 20th century viral pneumonia radiotherapy treatment using modern fluoroscopy and evaluated it according to current dose guidelines. Monte Carlo was used to assess the dose distribution on an anthropomorphic phantom. Critical organs were: skin, breasts, esophagus, ribs, vertebrae, heart, thymus, and spinal cord. A 100 kV_p beam with 3 mm Al HVL, 25 × 25 cm² posterior-anterior (PA) field and 50 cm source-to-surface distance were simulated. Simulations had a resolution of 0.4 × 0.4 × 0.06 cm³ and a 6% uncertainty. Hundred percent dose was normalized to the skin surface and results were displayed in axial, coronal, and sagittal planes. Dose volume histograms were generated in MATLAB for further analysis. Prescription doses of 0.3, 0.5, and 1.0 Gy were applied to the 15% isodose for organ-dose comparison to current tolerances and potential risk of detriment. Ninety-five and ninety-seven percent of the right and left lung volumes, respectively, were well-covered by the 15% isodose line. For the 0.3, 0.5, and 1.0 Gy prescriptions, the maximum skin doses were 2.9, 4.8, and 9.6 Gy compared to a 2.0 Gy transient erythema dose threshold; left/right lung maximum doses were 1.44/1.46, 2.4/2.4, and 4.8/4.9 Gy compared to a 6.5 Gy pneumonitis and 30 Gy fibrosis thresholds; maximum heart doses were 0.5, 0.9, and 1.8 Gy compared to the 0.5 Gy ICRP-recommendation; maximum spinal cord doses were 1.4, 2.3, and 4.6 Gy compared to 7.0 Gy single fraction dose threshold. Maximum doses to other critical organs were below modern dose thresholds. A 100 kV_p PA field could deliver a 0.3 Gy or 0.5 Gy dose without risk of complications. However, a 1.0 Gy dose treatment could be problematic. Critical organ doses could be further reduced if more than one treatment field is used.

Radiation exposure of a mobile 3D C-arm with large flat-panel detector for intraoperative imaging and navigation - an experimental study using an anthropomorphic Alderson phantom

Background

Intraoperative 3-dimensional (3D) navigation is increasingly being used for pedicle screw placement. For this purpose, dedicated mobile 3D C-arms are capable of providing intraoperative fluoroscopy-based 3D image data sets. Modern 3D C-arms have a large field of view, which suggests a higher radiation exposure. In this experimental study we therefore investigate the radiation exposure of a new mobile 3D C-arm with large flat-panel detector to a previously reported device with regular flat-panel detector on an Alderson phantom.

Methods

We measured the radiation exposure of the Vision RFD 3D (large 30 × 30 cm detector) while creating 3D image sets as well as standard fluoroscopic images of the cervical and lumbar spine using an Alderson phantom. The dosemeter readings were then compared with the radiation exposure of the previous model Vision FD Vario 3D (smaller 20 × 20 cm detector), which had been examined identically in advance and published elsewhere.

Results

The larger 3D C-arm induced lower radiation exposures at all dosemeter sites in cervical 3D scans as well as at the sites of eye lenses and thyroid gland in lumbar 3D scans. At ​​male and especially female gonads in lumbar 3D scans, however, the larger 3D C-arm showed higher radiation exposures compared with the smaller 3D C-arm. In lumbar fluoroscopic images, the dosemeters near/in the radiation field measured a higher radiation exposure using the larger 3D C-arm.

Conclusions

The larger 3D C-arm offers the possibility to reduce radiation exposures for specific applications despite its larger flat-panel detector with a larger field of view. However, due to the considerably higher radiation exposure of the larger 3D C-arm during lumbar 3D scans, the smaller 3D C-arm is to be recommended for short-distance instrumentations (mono- and bilevel) from a radiation protection point of view. The larger 3D C-arm with its enlarged 3D image set might be used for long instrumentations of the lumbar spine. From a radiation protection perspective, the use of the respective 3D C-arm should be based on the presented data and the respective application.

Pedicle Screw Insertion: Is O-Arm-Based Navigation Superior to the Conventional Freehand Technique? A Systematic Review and Meta-Analysis

BACKGROUND

Although O-arm-based navigation (ON) has been considered a better choice than the conventional freehand (FH) technique for spine surgery, clinical evidence showing the accuracy of ON compared with the FH technique is limited. The purpose of this study was to evaluate the accuracy of pedicle screw insertion under ON compared with the FH technique.

METHODS

The Cochrane Library, Ovid, Web of Science, PubMed, Embase, and CNKI online databases were searched up to January 2020. Because only a few randomized controlled trials were anticipated, prospective and retrospective comparative studies were also evaluated to compare the accuracy of pedicle screw insertion between ON and FH. Statistical analysis was performed using Stata 16.0. The primary outcomes extracted from articles that met the selection criteria were expressed as odds ratios for dichotomous outcomes with a 95% confidence interval. A χ² test and I² statistics were used to evaluate heterogeneity.

RESULTS

A total of 20 reviews were included in this meta-analysis without identifying additional studies from the references of published articles. These reviews included 1422 patients and 9982 screws. ON was used to insert 4797 pedicle screws and 5185 pedicle screws were inserted using the conventional FH technique with C-arm assistance. The meta-analysis showed that ON is significantly more accurate than FH pedicle screw insertion (odds ratio, 2.46; 95% confidence interval, 1.92-3.16; I² = 43.4%; P = 0.021). I² indicates that the studies have a moderate statistical heterogeneity; subgroup analysis decreased heterogeneity significantly.

CONCLUSIONS

Compared with conventional methods, navigation provides greater accuracy in the placement of pedicle screws, accelerates the insertion, and reduces the complications associated with screw insertion. However, it may increase exposure time to radiation, which may harm the patient's or surgeon's health.

A visual odometry base-tracking system for intraoperative C-arm guidance

PURPOSE

C-arms are portable X-ray devices used to generate radiographic images in orthopedic surgical procedures. Evidence suggests that scouting images, which are used to aid in C-arm positioning, result in increased operation time and excess radiation exposure. C-arms are also primarily used qualitatively to view images, with limited quantitative functionality. Various techniques have been proposed to improve positioning, reduce radiation exposure, and provide quantitative measuring tools, all of which require accurate C-arm position tracking. While external stereo camera systems can be used for this purpose, they are typically considered too obtrusive. This paper therefore presents the development and verification of a low-profile, real-time C-arm base-tracking system using computer vision techniques.

METHODS

The proposed tracking system, called OPTIX (On-board Position Tracking for Intraoperative X-rays), uses a single downward-facing camera mounted to the base of a C-arm. Relative motion tracking and absolute position recovery algorithms were implemented to track motion using the visual texture in operating room floors. The accuracy of the system was evaluated in a simulated operating room mounted on a real C-arm.

RESULTS

The relative tracking algorithm measured relative translation position changes with errors of less than 0.75% of the total distance travelled, and orientation with errors below 5% of the cumulative rotation. With an error-correction step incorporated, OPTIX achieved C-arm repositioning with translation errors of less than [Formula: see text]  mm and rotation errors of less than [Formula: see text]. A display based on the OPTIX measurements enabled consistent C-arm repositioning within 5 mm of a previously stored reference position.

CONCLUSION

The system achieved clinically relevant accuracies and could result in a reduced need for scout images when re-acquiring a previous position. We believe that, if implemented in an operating room, OPTIX has the potential to reduce both operating time and harmful radiation exposure to patients and surgical staff.

Examination of fluoroscopy monitor as a source of indirect bacterial contamination in orthopaedic surgery

Background

Surgical site infection is a well-documented complication of surgery. While contact with fomites represents a recognised source of contamination, electrostatic charge can cause contamination without surface contact as shown in previous studies evaluating operating room equipment. In cases requiring fluoroscopy, an intraoperative X-ray method, it is common for a surgeon to point to the associated monitor, particularly when teaching. This close proximity without direct contact poses a theoretical risk of contamination due to potential electrostatic forces.

Aim/Objective

To assess whether a gloved finger could be contaminated by a fluoroscopy monitor without direct contact.

Methods

Using a laser-guided level, a sterile, gloved finger was traversed side-to-side, top-to-bottom, across a fluoroscopy monitor used during surgery at distances of 1 cm, 2 cm, 4 cm and 8 cm. Two negative controls and a positive control were collected for comparison. Specimens were inoculated onto agar plates and incubated for 48 h at 37 °C. Following incubation, samples were analysed for growth and the number of colonies was recorded. This was repeated during 10 randomly selected operative cases using fluoroscopy for a total of 70 samples.

Results

No bacterial growth was identified as a result of inoculation on any of the 70 experimental or control specimens.

Discussion

We conclude that the practice of pointing to a fluoroscopy monitor for educational or other purposes is unlikely to increase the risk of glove contamination.

C-Arm-Free Circumferential Minimally Invasive Surgery for Adult Spinal Deformity: Technical Note

BACKGROUND

Circumferential minimally invasive surgery (cMIS), as a technique for reducing the complications of adult spinal deformity surgery, is receiving considerable attention. Conventional cMIS is performed using intraoperative fluoroscopy. In this work, we describe a new cMIS technique without using C-arm fluoroscopy for correcting adult spinal deformities.

CASE DESCRIPTION

A 70-year-old woman with symptomatic adult spinal deformity was referred to our hospital. The patient's daily life has been affected by severe low back pain for more than 4 years. The surgery was performed without C-arm fluoroscopy. The percutaneous pedicle screws and intervertebral cages were inserted only under navigation guidance. The patient was successfully treated with surgery, and her low back pain was well controlled. Her clinical outcomes were as follows: Oswestry Disability Index improved from 64% to 14% and the low back pain visual analog scale score improved from 75 mm to 24 mm at 1 year of final follow-up.

CONCLUSIONS

C-arm-free cMIS for adult spinal deformity is a useful technique that reduces percutaneous screw and cage misplacement. With this new technique, the surgeons and the operation room staff can avoid the risk of an adverse event of intraoperative radiation.

Effect of Instrument Navigation on C-arm Radiation and Time during Spinal Procedures: A Clinical Evaluation

Introduction

As minimally invasive spine surgery gains popularity, a focused effort must be made to reduce intraoperative radiation exposure to levels as low as reasonably achievable. Here, we demonstrate the clinical efficacy of a novel technology to aid in instrument navigation that aims to reduce intraoperative radiation exposure, number of fluoroscopic images, and time required to perform the most radiation intensive portions of a multitude of spinal procedures.

Methods

An internally randomized controlled study was performed over a 1-month period in order to clinically evaluate the effect of the C-arm assisted instrument tracking system, TrackX, on surgeon workflow, time, and radiation emitted. Three surgeons performed multiple spinal procedures on a total of 10 study patients and an additional 3 control patients. The surgeries encompassed minimally invasive spinal techniques and spanned extreme lateral interbody fusion, oblique lumbar interbody fusion, transforaminal lumbar interbody fusion along with percutaneous iliac screw placement, hardware removal, and kyphoplasty. The tasks studied included skin marking, first dilator insertion, localization for hardware placement and hardware removal.

Results

Overall radiation reduction was 83% (P < .0001). Overall reduction in x-rays taken was 78% (P < .0001). Overall time reduction was 81% (P = .0003). Statistical significance held for each surgeon studied and for nearly every procedure type. In these 10 study procedures, over 2 hours of overall operating room time was saved, all while requiring negligible set up time and no system calibration or supplementary x-rays to be taken. There were no adverse outcomes for any study patient, and there was no case where TrackX was not able to successfully complete a given portion of a procedure.

Conclusions

TrackX instrument navigation is a clinically efficacious and accurate instrument tracking modality. This is the first instrument navigational technology that reduces radiation exposure and images required to complete a procedure while decreasing operative time. TrackX thus allows increased surgical efficiency while increasing operative efficiency and improving intraoperative safety.

Level of Evidence

2.

O-arm navigation versus C-arm guidance for pedicle screw placement in spine surgery: a systematic review and meta-analysis

BACKGROUND

O-arm and C-arm are commonly used in spine surgery to guide pedicle screw placement. However, concerning the accuracy and efficiency of them, no systematical review and meta-analyses are available to help surgeons make comparisons.

PURPOSES

This study aims to investigate the accuracy and efficiency of O-arm-navigated versus C-arm-guided pedicle screw placement in thoracic and lumbar spine surgery. It would help surgeons choose the optimal technique for pedicle screw placement.

PATIENTS AND METHODS

A systematic review and meta-analyses were performed after searching the PubMed, Embase, and Cochrane databases to identify all studies that assessed the accuracy and efficiency of navigation coupled with O-arm and conventional C-arm fluoroscopy.

RESULTS

Eight studies were finally recruited in this systematic review, all of which reported pedicle screw placement outcomes related to accuracy or efficiency in both C-arm and O-arm groups. Five studies showed higher screw insertion accuracy in the O-arm group, while one study showed no significant difference. And the pooled results also indicated that the incidence of screw misplacement in the C-arm groups is higher. Moreover, the pooled results from five studies indicated no significant difference in insertion time between C-arm and O-arm.

CONCLUSIONS

Navigation coupled with O-arm imaging displayed a lower efficiency outcome in pedicle screw placement compared to conventional C-arm fluoroscopy. However, in terms of accuracy, O-arm navigation had significant advantages in accuracy over conventional C-arm fluoroscopy.

Radiation Exposure of Anaesthetists Visualised by Real-time Dosimetry

BACKGROUND

Chronic exposure to occupational ionising radiation is seen as one reason for elevated cancer prevalence.

OBJECTIVE

The aim of this retrospective study was to evaluate radiation exposure of anaesthetists by real-time dosimetry.

METHODS

Data of 296 patients were analyzed. Ten types of trauma operation procedures including osteosynthesis of upper and lower extremity fractures and minimally invasive stabilisation of traumatic and osteoporotic vertebral fractures were accomplished. Evaluation was performed by an occupational dosimetry system, which visualises anaesthetists radiation exposure feedback compared to surgeons in real-time.

RESULTS

A significantly lower radiation exposure to anaesthetists compared to surgeons was observed in four types of operative procedures: Plate fixation of proximal humerus fractures, osteosynthesis of proximal femoral fractures, stabilisation of traumatic and osteoporotic vertebral fractures. In four types of operations (plate osteosynthesis of proximal humeral, distal radial and tibial fractures and intramedullary nailing of the clavicle), anaesthetists` amount of radiation exceeded one-third of the surgeons' exposure, especially if the C-arm tube was positioned close to the anaesthetists work station at the patients' head.

CONCLUSION

By using the occupational radiation dose monitoring system, radiation exposure to anaesthetists was visualised in real-time during trauma operations. Radiation exposure of anaesthetists depends on the type of operation and the position of the C-arm. The system may help to increase anaesthetists` awareness concerning radiation exposure and to enhance compliance in using radiation protection techniques.

A Comparison of Image Quality and Radiation Exposure Between the Mini C-Arm and the Standard C-Arm

Background: The use of intraoperative fluoroscopy has become mandatory in osseous hand surgery. Due to its overall practicality, the mini C-arm has gained popularity among hand surgeons over the standard C-arm. This study compares image quality and radiation exposure for patient and staff between the mini C-arm and the standard C-arm, both with flat panel technology. Methods: An observer-based subjective image quality study was performed using a contrast detail (CD) phantom. Five independent observers were asked to determine the smallest circles discernable to them. The results were plotted in a graph, forming a CD curve. From each curve, an image quality figure (IQF) was derived. A lower IQF equates to a better image quality. The patients' entrance skin dose was measured, and to obtain more information about the staff exposure dose, a perspex hand phantom was used. The scatter radiation was measured at various distances and angles relative to a central point on the detector. Results: The IQF was significantly lower for the mini C-arm resulting in a better image quality. The patients' entrance dose was 10 times higher for the mini C-arm as compared with the standard C-arm, and the scatter radiation threefold. Conclusions: Due to its improved image quality and overall practicality, the mini C-arm is recommended for hand surgical procedures. To ensure that the surgeons' radiation exposure is not exceeding the safety limits, monitoring radiation exposure using mini C-arms with flat panel technology during surgery should be done in a future clinical study.

A study protocol for a randomised controlled trial evaluating the effects of intraoperative computed tomography on the outcomes of zygomatic fractures

Background

Zygomaticomaxillary complex (ZMC) and zygomatic arch (ZA) fractures are common injuries resulting from facial trauma and frequently require surgical management (Huang et al., Craniomaxillofac Trauma Reconstr 8(4):271-6, 2015). A substantial number of post-operative functional and cosmetic complications can arise from the surgical management of these fractures. These include scarring, inadequate facial profile restoration, facial asymmetries and diplopia (Ellis et al. J Oral Maxillofac Surg 54(4):386-400, 1996; Yang et al. Oral Maxillofac Surg Clin North Am 23(1):31-45, 2011; Kloss et al. Int J Oral Maxillofac Surg 40(1):33-7, 2011). Intuitively, most of these aforementioned complications arise as a result of inadequate fracture reduction; however, current standard practice is to assess reduction post-operatively through plain radiographs or computed tomography (CT) scans. The role of intra-operative CT scanning to assess the reduction of ZMC/ZA fractures and the potential impact on complications, has thus far not been established.

Methods

This is a prospective randomised controlled trial currently being undertaken at the Royal Brisbane and Women’s Hospital. All patients who require operative management of their ZMC or ZA fractures are offered enrollment in the trial. The patients are randomised into two groups: interventional (intra-operative CT) and control (no intra-operative CT). All patients in each group will have post-operative radiographs taken. From these radiographs, the reduction of the ZMC and/or ZA fracture is graded by a blinded assessor. Patients will be reviewed in clinic at 1 week and 6 weeks post-surgery. During these consultations, all patients will be assessed for scarring, diplopia, facial profile restoration and need for revision surgery.

Discussion

Many complications associated with surgical management of ZMC and ZA fractures involve poor aesthetic results as a direct consequence of inadequate fracture reduction. Inadequate fracture reduction is predictable given that small incisions are used and only limited visualisation of the fractures is possible during the procedure. This is due to a desire to limit scarring and reduce the risk of damage to vital structures in an aesthetically sensitive region of the body. It follows that an intraoperative adjunctive tool such as a CT scan, which can assist in visualisation of the fractures and the subsequent reduction, could potentially improve reduction and reduce complications.

Trial registration

Australian New Zealand Clinical Trials Registry, ACTRN12616000693426. Registered on 26 May 2016.

Electronic supplementary material

The online version of this article (10.1186/s13063-019-3625-8) contains supplementary material, which is available to authorized users.

Co-localized augmented human and X-ray observers in collaborative surgical ecosystem

PURPOSE

Image-guided percutaneous interventions are safer alternatives to conventional orthopedic and trauma surgeries. To advance surgical tools in complex bony structures during these procedures with confidence, a large number of images is acquired. While image-guidance is the de facto standard to guarantee acceptable outcome, when these images are presented on monitors far from the surgical site the information content cannot be associated easily with the 3D patient anatomy.

METHODS

In this article, we propose a collaborative augmented reality (AR) surgical ecosystem to jointly co-localize the C-arm X-ray and surgeon viewer. The technical contributions of this work include (1) joint calibration of a visual tracker on a C-arm scanner and its X-ray source via a hand-eye calibration strategy, and (2) inside-out co-localization of human and X-ray observers in shared tracking and augmentation environments using vision-based simultaneous localization and mapping.

RESULTS

We present a thorough evaluation of the hand-eye calibration procedure. Results suggest convergence when using 50 pose pairs or more. The mean translation and rotation errors at convergence are 5.7 mm and [Formula: see text], respectively. Further, user-in-the-loop studies were conducted to estimate the end-to-end target augmentation error. The mean distance between landmarks in real and virtual environment was 10.8 mm.

CONCLUSIONS

The proposed AR solution provides a shared augmented experience between the human and X-ray viewer. The collaborative surgical AR system has the potential to simplify hand-eye coordination for surgeons or intuitively inform C-arm technologists for prospective X-ray view-point planning.

Behaviour and knowledge skill levels of orthopedic surgeons about radiation safety and fluoroscopy use: A survey analysis

OBJECTIVE

The aim of this study was to evaluate the behaviour and knowledge skill levels of Turkish orthopedic surgeons about fluoroscopy usage and radiation safety.

METHODS

The questionnaire, consisting of nineteen questions, was sent to orthopaedic surgeons and requested by a total of 323 surgeons online. The questions were about personal information, training and behaviours related to radiation and fluoroscopy usage, and the use of protective equipment.

RESULTS

A total of 277 individuals completed the questionnaire. The answers of 180 surgeons whose working duration was more than 1 year and also who participated in at least one fluoroscopy requiring operation per week, were analysed. 22 (12%) participants answered that they were trained on fluoroscopy usage. Sixty people (33.3%) reported that they did not use any protective equipment regularly. The most commonly used protection methods were lead aprons 123 (68.3%). Thyroid protectors were used by 92 participants (52.1%). There was no significant difference between the groups when comparing the use of protective equipment according to the academic title. Only 19 (10.6%) of the surgeons noted that they used dosimeter regularly, and 15 (83.3%) of them reported that they controlled their dosimeters.

CONCLUSION

In this study, Orthopedic surgeons were found not to be adequately trained about use and risks of fluoroscopy and also not to be equipped about methods for preventing radiation damage.

The Surgical Approach Visualization and Navigation (SAVN) System reduces radiation dosage and surgical trauma due to accurate intraoperative guidance

OBJECT

The intraoperative fluoroscopy has been widely used in modern neuro-spinal surgery due to the overwhelming trend toward minimal-access surgery. However, both patients and surgical personnel were under ionizing-radiation exposure during fluoroscopy usage. Since the fluoroscopy constitutes the vast majority of radiation exposure for both surgeons and patients, the development and improvement of new interventional possibilities are of great importance and interests.

PATIENTS AND METHODS

A total of 20 patients were included in the current study, who received thoracic-spinal tumor resection via posterior midline approach. In comparison to the conventional C-Arm mobile fluoroscopy machine, the Surgical Approach Visualization and Navigation (SAVN) System was used to evaluate the effectiveness in reducing radiation.

RESULTS

The pain intensity and Japanese Orthopedic Association Score were equally ameliorated in patients of two groups. However, compared to C-arm group, the SAVN significantly reduced the screening time from 26.8 + 12.4 to 17.1 + 9.2 s (36.2% radiation reduction, P < 0.05), which was mainly due to the significant reduction of radiation attempts (from 12.8 + 4.9 to 7.1 + 5.5 times, P < 0.05). For patients, the direct and scatter radiation dose dropped 30.4% (P < 0.05) in the surgical region and 47.6% (P < 0.01) in the non-surgical region by using the SAVN System. Additionally, the tumor diameter/skin incision ratio increased from 0.39 + 0.4 to 0.47+ 0.28 after SAVN usage. Meanwhile, thedosimeter showed that the radiation dose to the primary surgeon was also lower in the SAVN group (72.1% reduction, P < 0.01).

CONCLUSION

Comparing the conventional C-arm, the SAVN System based thoracic-spinal surgery significantly lowered radiation duration and dosage application towards both surgeons and patients.

Prototype system for interventional dual-energy subtraction angiography

Dual-energy subtraction angiography (DESA) using fast kV switching has received attention for its potential to reduce misregistration artifacts in thoracic and abdominal imaging where patient motion is difficult to control; however, commercial interventional solutions are not currently available. The purpose of this work was to adapt an x-ray angiography system for 2D and 3D DESA. The platform for the dual-energy prototype was a commercially available x-ray angiography system with a flat panel detector and an 80 kW x-ray tube. Fast kV switching was implemented using custom x-ray tube control software that follows a user-defined switching program during a rotational acquisition. Measurements made with a high temporal resolution kV meter were used to calibrate the relationship between the requested and achieved kV and pulse width. To enable practical 2D and 3D imaging experiments, an automatic exposure control algorithm was developed to estimate patient thickness and select a dual-energy switching technique (kV and ms switching) that delivers a user-specified task CNR at the minimum air kerma to the interventional reference point. An XCAT-based simulation study conducted to evaluate low and high energy image registration for the scenario of 30-60 frame/s pulmonary angiography with respiratory motion found normalized RMSE values ranging from 0.16% to 1.06% in tissue-subtracted DESA images, depending on respiratory phase and frame rate. Initial imaging in a porcine model with a 60 kV, 10 ms, 325 mA / 120 kV, 3.2 ms, 325 mA switching technique demonstrated an ability to form tissue-subtracted images from a single contrast-enhanced acquisition.

Mobile C-Arm with a CMOS detector: Technical assessment of fluoroscopy and Cone-Beam CT imaging performance

PURPOSE

Indirect-detection CMOS flat-panel detectors (FPDs) offer fine pixel pitch, fast readout, and low electronic noise in comparison to current a-Si:H FPDs. This work investigates the extent to which these potential advantages affect imaging performance in mobile C-arm fluoroscopy and cone-beam CT (CBCT).

METHODS

FPDs based on CMOS (Xineos 3030HS, 0.151 mm pixel pitch) or a-Si:H (PaxScan 3030X, 0.194 mm pixel pitch) sensors were outfitted on equivalent mobile C-arms for fluoroscopy and CBCT. Technical assessment of 2D and 3D imaging performance included measurement of electronic noise, gain, lag, modulation transfer function (MTF), noise-power spectrum (NPS), detective quantum efficiency (DQE), and noise-equivalent quanta (NEQ) in fluoroscopy (with entrance air kerma ranging 5-800 nGy per frame) and cone-beam CT (with weighted CT dose index, CTDI_w , ranging 0.08-1 mGy). Image quality was evaluated by clinicians in vascular, orthopaedic, and neurological surgery in realistic interventional scenarios with cadaver subjects emulating a variety of 2D and 3D imaging tasks.

RESULTS

The CMOS FPD exhibited ~2-3× lower electronic noise and ~7× lower image lag than the a-Si:H FPD. The 2D (projection) DQE was superior for CMOS at ≤50 nGy per frame, especially at high spatial frequencies (~2% improvement at 0.5 mm^-1 and ≥50% improvement at 2.3 mm^-1 ) and was somewhat inferior at moderate-high doses (up to 18% lower DQE for CMOS at 0.5 mm^-1 ). For smooth CBCT reconstructions (low-frequency imaging tasks), CMOS exhibited ~10%-20% higher NEQ (at 0.1-0.5 mm^-1 ) at the lowest dose levels (CTDI_w ≤0.1 mGy), while the a-Si:H system yielded slightly (~5%) improved NEQ (at 0.1-0.5 lp/mm) at higher dose levels (CTDI_w ≥0.6 mGy). For sharp CBCT reconstructions (high-frequency imaging tasks), NEQ was ~32% higher above 1 mm^-1 for the CMOS system at mid-high-dose levels and ≥75% higher at the lowest dose levels (CTDI_w ≤0.1 mGy). Observer assessment of 2D and 3D cadaver images corroborated the objective metrics with respect to a variety of pertinent interventional imaging tasks.

CONCLUSION

Measurements of image noise, spatial resolution, DQE, and NEQ indicate improved low-dose performance for the CMOS-based system, particularly at lower doses and higher spatial frequencies. Assessment in realistic imaging scenarios confirmed improved visibility of fine details in low-dose fluoroscopy and CBCT. The results quantitate the extent to which CMOS detectors improve mobile C-arm imaging performance, especially in 2D and 3D imaging scenarios involving high-resolution tasks and low-dose conditions.

Surgeon's and patient's radiation exposure during percutaneous thoraco-lumbar pedicle screw fixation: A prospective multicenter study of 100 cases

HYPOTHESIS

Percutaneous pedicle screw fixations (PPSF) are increasingly used in spine surgery, minimizing morbidity through less muscle breakdown but at the cost of intraoperative fluoroscopic guidance that generates high radiation exposure. Few studies have been conducted to measure them accurately.

MATERIAL AND METHODS

The objective of our study is to quantify, during a PPSF carried out in different experimented centers respecting current radiation protection recommendations, this irradiation at the level of the surgeon and the patient. We have prospectively included 100 FPVP procedures for which we have collected radiation doses from the main operator. For each procedure, the doses of whole-body radiation, lens and extremities were measured.

RESULTS

Our results show a mean whole body, extremity and lens exposure dose per procedure reaching 1.7±2.8μSv, 204.7±260.9μSv and 30.5±25.9μSv, respectively. According to these values, the exposure of the surgeon's extremities and lens will exceed the annual limit allowed by the International Commission on Radiological Protection (ICRP) after 2440 and 4840 procedures respectively.

CONCLUSION

Recent European guidelines will reduce the maximum annual exposure dose from 150 to 20mSv. The number of surgical procedures to not reach the eye threshold, according to our results, should not exceed 645 procedures per year. Pending the democratization of neuronavigation systems, the use of conventional fluoroscopy exposes the eyes in the first place. Therefore they must be protected by leaded glasses.

LEVEL OF PROOF

IV, case series.

Viewpoint planning for quantitative coronary angiography

PURPOSE

In coronary angiography, the condition of myocardial blood supply is assessed by analyzing 2-D X-ray projections of contrasted coronary arteries. This is done using a flexible C-arm system. Due to the X-ray immanent dimensionality reduction projecting the 3-D scene onto a 2-D image, the viewpoint is critical to guarantee an appropriate view onto the affected artery and, thus, enable reliable diagnosis. In this work, we introduce an algorithm computing optimal viewpoints for the assessment of coronary arteries without the need for 3-D models.

METHODS

We introduce the concept of optimal viewpoint planning solely based on a single angiographic X-ray image. The subsequent viewpoint is computed such that it is rotated precisely around a vessel, while minimizing foreshortening.

RESULTS

Our algorithm reduces foreshortening substantially compared to the input view and completely eliminates it for [Formula: see text] rotations. Rotations around isocentered foreshortening-free vessels passing the isocenter are exact. The precision, however, decreases when the vessel is off-centered or foreshortened. We evaluate worst-case boundaries, providing insight in the maximal inaccuracies to be expected. This can be utilized to design viewpoints guaranteeing desired requirements, e.g., a true rotation around the vessel of at minimum [Formula: see text]. In addition, a phantom study is performed investigating the impact of input views to 3-D quantitative coronary angiography (QCA).

CONCLUSION

We introduce an algorithm for optimal viewpoint planning from a single angiographic X-ray image. The quality of the second viewpoint-i.e., vessel foreshortening and true rotation around vessel-depends on the first viewpoint selected by the physician; however, our computed viewpoint is guaranteed to reduce the initial foreshortening. Our novel approach uses fluoroscopy images only and, thus, seamlessly integrates with the current clinical workflow for coronary assessment. In addition, it can be implemented in the QCA workflow without increasing user interaction, making vessel-shape reconstruction more stable by standardizing viewpoints.

C-arm fluoroscopy in orthopaedic surgical practice

The use of C-arm fluoroscopy in intraoperative orthopaedic procedures has become an important tool in modern orthopaedic surgical practice. It enhances the technical proficiency of the surgeon in addition to reducing the morbidity and length of hospital stay of the patient. Despite the documented benefits of this device, there has been a growing concern about the increased radiation exposure to the surgical team. We therefore present the review of the literature on the usefulness of C-arm fluoroscopy, pitfalls in application of the machine as well as the harmful radiation effects and precautionary measures that need to be observed when using the C-arm fluoroscopy in orthopaedic surgical procedures.

Automatic intraoperative stitching of nonoverlapping cone-beam CT acquisitions

PURPOSE

Cone-beam computed tomography (CBCT) is one of the primary imaging modalities in radiation therapy, dentistry, and orthopedic interventions. While CBCT provides crucial intraoperative information, it is bounded by a limited imaging volume, resulting in reduced effectiveness. This paper introduces an approach allowing real-time intraoperative stitching of overlapping and nonoverlapping CBCT volumes to enable 3D measurements on large anatomical structures.

METHODS

A CBCT-capable mobile C-arm is augmented with a red-green-blue-depth (RGBD) camera. An offline cocalibration of the two imaging modalities results in coregistered video, infrared, and x-ray views of the surgical scene. Then, automatic stitching of multiple small, nonoverlapping CBCT volumes is possible by recovering the relative motion of the C-arm with respect to the patient based on the camera observations. We propose three methods to recover the relative pose: RGB-based tracking of visual markers that are placed near the surgical site, RGBD-based simultaneous localization and mapping (SLAM) of the surgical scene which incorporates both color and depth information for pose estimation, and surface tracking of the patient using only depth data provided by the RGBD sensor.

RESULTS

On an animal cadaver, we show stitching errors as low as 0.33, 0.91, and 1.72 mm when the visual marker, RGBD SLAM, and surface data are used for tracking, respectively.

CONCLUSIONS

The proposed method overcomes one of the major limitations of CBCT C-arm systems by integrating vision-based tracking and expanding the imaging volume without any intraoperative use of calibration grids or external tracking systems. We believe this solution to be most appropriate for 3D intraoperative verification of several orthopedic procedures.

Accuracy of C-arm measurements in assessment of paediatric femoral fracture shortening

PURPOSE

Spica casting of femoral shaft fractures is standard practice for young children. In 1983, Dr. Rang published an illustration demonstrating that radiographs can be misleading when measuring femoral fracture shortening. Today, fluoroscopy is used to determine shortening after closed reduction and spica casting. This paper aims to determine the accuracy of fluoroscopy when measuring 25 mm of shortening in a femur fracture sawbone model.

METHODS

Magnification, elevation and angulation were evaluated using a femur fracture sawbone model with a fixed overlap of 25 mm. Two C-arm machines used in clinical practice were studied: the OEC 9900 Elite GE C-arm and the Fluoroscan InSight mini C-arm.

RESULTS

The OEC 9900 Elite GE C-arm demonstrated a 1.75 × magnification. The Fluoroscan InSight mini C-arm demonstrated a 2.5 × magnification. An 11% and a 17% magnification with elevation of the femur to 8 cm occurred using the OEC 9900 Elite GE and the Fluoroscan InSight mini C-arm respectively. Changing the tube angulation from 0° to 60° resulted in a 36% and 16% change in measured femur fracture shortening on the OEC C-arm and Fluoroscan mini C-arm respectively.

CONCLUSION

C-arm images are inaccurate. When measuring 25 mm of shortening of a paediatric femur fracture, each machine has a unique amount of magnification that should be determined and accounted for in clinical practice. Elevation of the femur above the C-arm receiver and angulation of the femur further increase the inaccuracies when measuring 25 mm of fracture shortening. Images perpendicular to the fracture are most accurate.

Single-camera visual odometry to track a surgical X-ray C-arm base

This study provides a framework for a single-camera odometry system for localizing a surgical C-arm base. An application-specific monocular visual odometry system (a downward-looking consumer-grade camera rigidly attached to the C-arm base) is proposed in this research. The cumulative dead-reckoning estimation of the base is extracted based on frame-to-frame homography estimation. Optical-flow results are utilized to feed the odometry. Online positional and orientation parameters are then reported. Positional accuracy of better than 2% (of the total traveled distance) for most of the cases and 4% for all the cases studied and angular accuracy of better than 2% (of absolute cumulative changes in orientation) were achieved with this method. This study provides a robust and accurate tracking framework that not only can be integrated with the current C-arm joint-tracking system (i.e. TC-arm) but also is capable of being employed for similar applications in other fields (e.g. robotics).

Intraoperative Registered Ultrasound and Fluoroscopy (iRUF) for dose calculation during prostate brachytherapy: Improved accuracy compared to standard ultrasound-based dosimetry

BACKGROUND AND PURPOSE

Intraoperative transrectal ultrasound dosimetry during low-dose-rate prostate brachytherapy is imprecise due to sonographic distortion caused by seed echoes and needle tracks that obscure seed positions or create false signals as well as traumatic edema. Here we report the results of a pilot study comparing a combined ultrasound and fluoroscopy-based seed localization method (iRUF) to standard ultrasound-based dosimetry (USD).

MATERIAL AND METHODS

Eighty patients undergoing permanent Pd-103 seed implantation for prostate cancer were prospectively enrolled. Seed implantation was performed using standard USD for intraoperative dose tracking. Upon implant completion, six X-ray images were intraoperatively acquired using a mobile C-arm and transverse ultrasound images of the implanted prostate were also acquired. Three-dimensional seed locations were reconstructed from X-ray images and registered to the ultrasound for iRUF dosimetry. Day 1 CT/MRI scans were performed for post-implant dosimetry. Prostate and urethral dosimetric parameters were separately calculated for analysis on iRUF, USD, and CT/MRI data sets. Differences and similarities between dosimetric values measured by iRUF, USD, and CT/MRI were assessed based on root mean squared differences, intraclass correlation coefficients (ICC), and Wilcoxon signed rank test.

RESULTS

Data from 66 eligible patients were analyzed. Compared to CT/MRI, iRUF dosimetry showed higher correlation with overall ICC of 0.42 (0.01 for USD) and significantly smaller root mean squared differences (overall 16.5 vs 21.5 for iRUF and USD) than USD for all prostate and urethral dosimetric parameters examined. USD demonstrated a tendency to overestimate dose to the prostate when compared to iRUF.

CONCLUSIONS

iRUF approximated post-implant CT/MRI prostate and urethral dosimetry to a greater degree than USD. A phase II trial utilizing iRUF for intraoperative dynamic plan modification is underway, with the goal to confirm capability to minimize and correct for prostate underdosage not otherwise detected.

Pose-aware C-arm for automatic re-initialization of interventional 2D/3D image registration

PURPOSE

In minimally invasive interventions assisted by C-arm imaging, there is a demand to fuse the intra-interventional 2D C-arm image with pre-interventional 3D patient data to enable surgical guidance. The commonly used intensity-based 2D/3D registration has a limited capture range and is sensitive to initialization. We propose to utilize an opto/X-ray C-arm system which allows to maintain the registration during intervention by automating the re-initialization for the 2D/3D image registration. Consequently, the surgical workflow is not disrupted and the interaction time for manual initialization is eliminated.

METHODS

We utilize two distinct vision-based tracking techniques to estimate the relative poses between different C-arm arrangements: (1) global tracking using fused depth information and (2) RGBD SLAM system for surgical scene tracking. A highly accurate multi-view calibration between RGBD and C-arm imaging devices is achieved using a custom-made multimodal calibration target.

RESULTS

Several in vitro studies are conducted on pelvic-femur phantom that is encased in gelatin and covered with drapes to simulate a clinically realistic scenario. The mean target registration errors (mTRE) for re-initialization using depth-only and RGB [Formula: see text] depth are 13.23 mm and 11.81 mm, respectively. 2D/3D registration yielded 75% success rate using this automatic re-initialization, compared to a random initialization which yielded only 23% successful registration.

CONCLUSION

The pose-aware C-arm contributes to the 2D/3D registration process by globally re-initializing the relationship of C-arm image and pre-interventional CT data. This system performs inside-out tracking, is self-contained, and does not require any external tracking devices.

Needle in a haystack: lost in transition

A lost needle during minimally invasive surgery is a cause of undue anxiety to the entire surgical team and also causes prolongation of surgical time. There is no literature reporting follow-up of any patient with needle left behind as they are considered as a 'never event' during a surgical procedure. Preventing such events needs vigilance on part of the surgeon and assistant. Here, we report a case of lost needle during performance of a robot-assisted nephron sparing surgery. The robot needed to be de-docked and converted to laparoscopy. After a thorough search, the needle was found to be lodged at an unusual place. A brief review of available literature is also provided alongside.

Successful Removal of Foreign Body Bronchus Using C-arm-guided Insertion of Fogarty Catheter through Plastic Bead

Foreign body aspiration is still a cause of significant morbidity in children. Complications occur due to difficulty in diagnosis and treatment. An eight-year-old child presented with a history of recurrent cough for 3 days. Rigid bronchoscopy under general anesthesia revealed plastic bead occupying right main bronchus. Removal with grasping forceps failed for several times due to spherical, smooth, and large bead. Finally, Fogarty catheter was passed through bead under C-arm guidance and successfully removed.